This invention relates generally to improvements in so-called hydraulic knife assemblies wherein a vegetable, such as a potato, is propelled by an hydraulic fluid into cutting engagement with knife blades positioned along a fluid flow path. More particularly, this invention relates to an improved hydraulic knife assembly having a cross-cut knife which can be moved across the flow path to sever a potato stuck therein, and thereby facilitate removal of the stuck potato so that normal cutting operation can be resumed.
Hydraulic knife assemblies in general are well known in the art, and typically comprise an array or grid of knife blades mounted along a flow path defined by an elongated tubular conduit. Pumping means are provided to entrain a vegetable product, such as a potato, with a propelling hydraulic fluid flow stream of relatively high velocity for flow through the conduit into cutting engagement with the knife blades. In production systems, vegetable products are pumped one at a time in relatively rapid succession with a propelling water stream for flow into and through the conduit, with the kinetic energy imparted to each product serving to drive the product past the knife blades. As a result, the vegetable products are cut into strips at a relatively rapid production rate, with the particular size and shape of the cut product strips being dictated by the geometry of the knife blades. For examples of hydraulic knife cutting assemblies of this general type used in production systems to cut potatoes into French fry strips, see U.S. Pat. Nos. 3,109,468; 3,116,772; and 4,423,652.
Hydraulic cutting systems of the type described above beneficially operate at relatively high production rates, whereby a substantial quantity of cut product can be generated in a relatively short period of time. However, on occasion, a vegetable product may be propelled into engagement with the knife blades with insufficient kinetic energy to carry the product through the knife assembly Instead, the product becomes jammed or stuck along the flow conduit at an upstream side of the knife blades, wherein the product blocks or obstructs passage of a succession of subsequent products pumped along the flow conduit.
In the past, a potato or the like lodged at the upstream side of the hydraulic knife assembly has required disassembly of a blade-carrying knife housing from a normal position mounted in-line with the tubular flow conduit. In this regard, the knife housing is normally separated from the flow conduit in a direction perpendicular to the product flow stream, for purposes of accessing and removing the stuck product. Unfortunately, a potato lodged at the upstream side of the knife blades typically bridges between the knife housing and the adjacent end of the flow conduit, such that the stuck potato obstructs knife housing removal. Substantial manual force has been necessary to separate the knife housing from the flow conduit, wherein this removal force must be sufficient to shear the stuck potato. The manual force required to remove the knife housing frequently exceeds the physical strength of many production line operators.
There exists, therefore, a significant need for improvements to hydraulic knife assemblies, particularly with respect to facilitating knife housing disassembly from a product flow conduit in the event that a product becomes stuck at the upstream side of the knife blades. The present invention fulfills this need and provides further related advantages.